Stand-alone continuous cardiac doppler pulse monitoring patch with integral visual and auditory alerts, and patch-display system and method

ABSTRACT

A stand-alone continuous cardiac Doppler pulse monitoring patch provides visual and auditory signals that a pulse is detected or not detected in a human subject. The invention is a small patch with a peel-away adhesive surface that is applied to the skin of the subject, preferably near a large artery. The adhesive surface of the patch includes a conductive medium to enhance transmission and reception of ultrasonic waves. The patch includes an integral power source, transmitters and receivers to send and detect reflected ultrasonic waves, a transducer to convert the reflected waves into an electrical signal, a processor to analyze the signal, a light to indicate the presence and strength of a pulse, and a speaker also to indicate the presence and strength of a pulse. The Doppler effect of waves reflecting from blood pumped from a heart is used to detect a pulse in the subject. The presence of a pulse is analyzed by the processor to determine the frequency and strength of blood flow. The processor causes the light to blink at a rate to indicate the frequency of rhythmic blood flow. In a further embodiment, the processor analyzes the strength of the blood flow and causes the light to increase or decrease in intensity to reflect the strength or weakness of the flow. The processor may also drive a speaker to emit sounds, such as beeps, that indicate the frequency and strength of blood flow. The absence of blood flow may be indicated by the absence of light or sound, or by separate light or auditory signals.

CLAIM OF PRIORITY TO PROVISIONAL APPLICATION (35 U.S.C. § 119(e))

This application claims priority under 35 U.S.C. § 119(e) fromprovisional patent Application No. 62/430,872 filed on Dec. 6, 2016 andfrom provisional application No. 62/523,765 filed on Jun. 22, 2017. The62/430,872 and 62/523,765 applications are incorporated herein byreference.

FIELD OF THE INVENTION

The present invention relates to a stand-alone continuous cardiacDoppler pulse monitoring patch that provides visual and auditory signalsthat blood flow is detected in a subject. More specifically, the presentinvention is a small patch that is applied to the skin of a subject,preferably near a large artery, and thereafter generates visual andaudible signals indicating the presence or absence of blood flow and, ifblood flow is detected, the frequency and strength of the flow. Theinvention is intended for use by emergency medical technicians, nurses,and doctors as a fast and reliable means to detect a pulse and, ifcalled for, initiate appropriate medical procedures, such ascardiopulmonary resuscitation (CPR).

BACKGROUND OF THE INVENTION

According to the American Heart Association(http://cpr.heart.org/AHAECC/CPRAndECC/General/UCM_477263_Cardiac-Arrest-Statistics.jsp),in the United States, since 2012, over half a million people haveexperienced cardiac arrest each year. Of those, about sixty percentoccurred outside a hospital and almost half of these involved theapplication of CPR by a lay person. The survival rate for thoseout-of-hospital cardiac arrests was about ten percent. The survival ratefor cardiac arrests in a hospital was also low at under thirty percent.A critical component of surviving cardiac arrest is quick treatment,such as the application of CPR. The decision to initiate CPR or otherprocedures to treat cardiac arrest is highly time sensitive. Thelikelihood of survival decreases by ten percent for every minute fromthe absence of a pulse to the return of spontaneous circulation (ROSC).

But, the physical palpitation of a pulse, usually by placing one or morefingers over a subject's artery, is difficult and subject to substantialerror. In one study, forty-five percent (66 out of 147) of medicallytrained first responders were unable to identify a pulse despite acarotid pulse and a blood pressure (BP) above or equal to 80 mmHg. Onlyfifteen percent (31 out of 206) of participants produced a correctdiagnosis of the absence of a pulse within ten seconds, which is therecommendation of the American Heart Association.

The use of an electrocardiograph (ECG) to detect a pulse is common, butproblematic, because the widely-recognized graphical pattern measureselectrical emissions from the heart muscle. But, these electricalsignals detected by the ECG do not measure the flow of blood in thesubject and it is not uncommon for telemetry to detect favorableelectrical emissions from the heart, even after the flow of blood hasceased and, in some instances, the subject has perished.

As noted above, physical palpitation for a pulse is widely used, but isalso substantially unreliable. Other means to detect blood flow includeDoppler pulse monitors, which have become more common in recent years,especially with the popularity and availability of fetal heart monitorssold at low prices to the general public. These monitors are designedfor intermittent checks. A typical Doppler monitor has an ultrasoundwand connected to a hand-held box by a cord. A conductive gel, toenhance transmission and reception of the ultrasonic waves, is squirtedonto the head of the wand which is placed against the subject. The boxamplifies the rhythmic sound of pulsing blood. But, such a device mustbe held by a technician and cannot be secured in place to provideconstant, real-time information. This continuing real-time informationis helpful for monitoring dynamic changes in an unstable or potentiallyunstable patient. For example, when CPR is administered, a hand-heldDoppler monitor cannot be held in place without another technician and,even if another technician is available to hold the monitor in place,the movement of the patient undergoing CPR makes holding the wand inplace and receiving useful return signals is extremely difficult. Yet,having real-time blood flow information is very helpful to a personperforming CPR, because it can inform the technician that CPR hassucceeded in achieving ROSC or that the patient is relapsing.

Even in the hospital setting existing devices pose problems. Forexample, when a subject requires an X-ray or other scan, existing ECGand Doppler monitors must usually be removed, leaving medical personnelwithout direct information about the subject's blood flow. As notedabove, since the passage of even very short periods of time candrastically reduce the chance of survival from cessation of blood flow,the lack of direct information can be a significant contributor tomortality.

Identifying and tracking the mechanical blood flow of the heart andlarge arterial vessels in real time is underutilized and important. Thecurrent system of isolated finger pulse or Doppler pulse checks ischallenging, even for medical professionals.

Needed is a Doppler pulse monitor that is easily and quickly applied toprovide constant, real-time detection of a subject's blood flow.

SUMMARY OF THE INVENTION

The present invention discloses a stand-alone continuous cardiac Dopplerpulse monitoring patch that provides visual and auditory signals that apulse is detected or not detected in a subject. The invention is a smallpatch with a peel-away adhesive surface that is applied to the skin of asubject, preferably near a large artery. The adhesive surface of thepatch includes a conductive medium to enhance transmission and receptionof ultrasonic waves. The patch includes a power source, transmitters andreceivers to send and detect reflected ultrasonic waves, a transducer toconvert an electrical signal into ultrasonic waves and convert thereflected waves into an electrical signal, a processor to control andanalyze the signals, a memory, a light to indicate the presence andstrength of a pulse, and a speaker also to indicate the presence andstrength of a pulse. The Doppler effect of waves reflecting from movingblood or a pulsing artery is used to detect a pulse in the subject. Thepresence of a pulse is analyzed by the processor to determine thefrequency and strength of blood flow. The processor causes a light toblink at a rate to indicate the frequency of rhythmic blood flow. In afurther embodiment, the processor analyzes the strength of the bloodflow and causes the light to increase or decrease in intensity toreflect the strength or weakness of the mechanical function of theheart. The processor may also drive a speaker to emit sounds, such asbeeps, that indicate the frequency and strength of blood flow. Theabsence of blood flow may be indicated by the absence of light or sound,or by separate or different light or auditory signals intended to conveythe absence of blood flow and potential emergency.

In an alternative embodiment, the continuous cardiac Doppler pulsemonitoring patch can be in the form of a “butterfly” patch designed tostraddle a subject's throat to monitor both left and right carotidarteries. In this butterfly patch embodiment, Doppler ultrasonic signalsare transmitted and received from each side of the butterfly patch, oneover the left carotid artery and the other over the right carotidartery. The Doppler signals detect the presence or absence of blood flowand pulse from each carotid artery and the information is processed, asdescribed above. The processed flow and pulse information can bedisplayed visually with a light mounted in the middle of the butterflypatch, over the subject's throat, as well as audibly with a speaker, asdescribed above. This butterfly patch arrangement can be useful if acervical collar has been placed around the patient's neck, because thevisual and audible signals of the patch can be seen through the frontopening provided in most cervical collars.

In an alternative embodiment, an integrated continuous cardiac Dopplerpulse monitoring patch includes a port to connect the patch byconductive wires to a separate display unit that can receive the bloodflow and pulse data from the patch and display the data visually on ascreen as well as provide auditory signals. The display unit can furtherprocess the data and display heart pulse (bpm) and blood flow (cm/s)rates in numerical and graphic forms. In a further embodiment, the patchand display unit can each include wireless transceivers to connect themand communicate the data wirelessly. In yet a further embodiment, thedisplay unit can provide processing and power for the patch, which isconsequently simplified and less expensive. In another embodiment, asimplified patch will have transducers to transmit and receiveultrasound waves and its own integrated power and wireless communicationcapability, thereby allowing the simplified patch to provide Dopplersignal data wirelessly to the display unit, which will process anddisplay the data.

The invention is intended for use by emergency medical technicians,nurses, and doctors as a fast and reliable means to detect a pulse and,if called for, initiate appropriate medical procedures, such ascardiopulmonary resuscitation (CPR).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a stand-alone continuous cardiac Doppler pulse-monitoringpatch with visual and auditory alerts of the present invention appliedto the neck of a patient.

FIG. 2 is a side view showing the layers the stand-alonepulse-monitoring patch.

FIG. 3 is a side, cut-away view showing the arrangement of components ofthe stand-alone pulse-monitoring patch invention.

FIG. 4 is a block diagram of the electronic circuitry of the stand-alonepulse-monitoring patch invention.

FIG. 5 shows a butterfly patch embodiment of the stand-alonepulse-monitoring patch invention applied to the neck of a patient.

FIG. 6 is a top view of the stand-alone pulse-monitoring butterfly patchinvention.

FIG. 7 is a bottom view of the stand-alone pulse-monitoring butterflypatch invention.

FIG. 8 is a side, cut-away view showing the arrangement of components ofthe stand-alone pulse-monitoring butterfly patch invention.

FIG. 9 is a block diagram of the electronic components of thestand-alone pulse-monitoring butterfly patch invention.

FIG. 10 is a schematic of a stand-alone pulse-monitoring patch connectedby a conductive cable to a display unit.

FIG. 11 is a side, cut-away view of a stand-alone pulse-monitoring patchwith a connector port for the conductive cable connection.

FIG. 12 is a block diagram of the components of a stand-alonepulse-monitoring patch and a display unit connected by a conductivecable.

FIG. 13 is a block diagram of the components of an alternate embodimentof a patch connected by a conductive cable to a display unit.

FIG. 14 is a schematic of a simplified pulse-monitoring patch connectedwirelessly to a display unit.

FIG. 15 is a block diagram of the components of an alternate embodimentof a patch and a display unit connected wirelessly.

FIG. 16 is a block diagram of the components of an alternate embodimentof a simplified patch and a display unit system.

DETAILED DESCRIPTION

FIG. 1 shows the stand-alone continuous Doppler heart monitor patch 10applied to the side of the neck of a patient 5. In this position, themonitor 10 will be close to the subject's neck artery 6, the rightcommon carotid artery 7B shown in FIG. 5, which is one of the betterarteries for detecting a pulse. The carotid artery is a useful positionto detect pulse, since it leaves the subject's chest free for CPR orother procedures to address cardiac arrest. The monitor 10 may be placedover other arteries, such as the femoral or radial arteries. When theon/off switch 19 is turned to the on position, the monitor 10 is placedover the subject's neck artery 6 and will begin transmitting ultrasonicsignals and detecting their reflections. When blood is flowing, theDoppler effect on the reflected signals will be identified by themonitor's 10 circuitry (16 in FIGS. 2 and 3), described below, asindicative of the blood's flow velocity, as well as of the frequency ofpulses as pulsations of the blood from the heart's pumps is recognized.This rhythmic pulse will be indicated by a blinking light 12 and mayfurther be indicated by an audible sound, such as a beep, from a speaker13.

FIG. 2 illustrates the parts of the monitor patch 10. The bottom of themonitor patch 10 is formed by a base 11, which supports the circuitry16. Under the base 11 is a conductive pad 14 to enhance transmission andreception of the ultrasonic waves from the circuitry 16 to the patient5. The conductive pad 14 may be a thermoplastic gel or a hydrogel.Hydrogels are hydrophilic networks of polymer chains and may befree-standing or contained within a thin membrane. Beneath theconductive pad 14 is a thin adhesive layer 15 to fix the monitor patch10 to the subject's skin. A peel-off layer 17 is disposed over theadhesive layer 15 to cover and preserve the adhesive until used. Mountedon the base 11 is the circuitry 16, described below. The circuitry 16may be mounted on a printed circuit board (PCB), which may be rigid,but, in a preferred embodiment, has some flexibility to conform to thesubject's body contours. Over the circuitry 16 are a light 12 and aspeaker 13 and, in some embodiments, a manual on/off switch 19. Aconductor 29 from the circuitry 16 to the light 12 allows electricity toflow to the light 12. Similarly, a conductor 30 controls electrical flowto the speaker 13, and conductors 31 provide connectivity between theon/off switch 19 on the circuitry 16.

FIGS. 3 and 4 show more detail of the circuitry 16. A power source 28,such as a small battery, provides integrated power to the electroniccomponents of the stand-alone monitor patch 10. A switch 32 controlspower or can activate the circuitry 16 from a low-power consumption reststate. A transducer 23 includes transmitters/receivers 18 arrayed in orover the base 11. The transmitters emit ultrasonic waves 26 and thereceivers detect reflected waves 27. The reflected wave signals 27 aredemodulated and analyzed by a processor 21 to determine whether thereflected wave pattern corresponds with Doppler shift signals indicativeof flowing blood. Since blood from a heart is pumped in rhythmic pulses,the received Doppler shift signals will indicate that pattern. Theprocessor 21 incorporates memory that can include data of Doppler shiftsignals indicative of flowing or pulsing blood. By comparing the Dopplershift signals 27 from the transducer 23 with data stored in the memoryassociated with the processor 21, the processor determines whether bloodflow has been detected. Once a blood flow is detected, the processor 21causes a light 12 (24 in FIG. 4) to blink in synchronization with therhythm of the heart's pulses. Similarly, the processor 21 will cause aspeaker 13 (25 in FIG. 4) to emit a sound, such as a beep, insynchronization with the rhythm of the heart's pulses. The processor 21will also analyze the reflected wave signals 27 for their strength bycomparing them to known values stored in the processor's 21 memory.Using the stored values, the processor 21 will cause the light 12 toblink with an intensity corresponding to the strength or weakness of thedetected pulse. Similarly, based on the stored values, the processor 21will cause the speaker 13 to beep with a volume corresponding to thestrength or weakness of the detected pulse.

The light 12 may be an LED. In a preferred embodiment, the LED light 12is capable of emitting different colors of light, such as red and green.For example, if a healthy pulse is detected by the monitor patch 10, theprocessor 21 will cause the light 12 to blink with a green colorindicating a healthy pulse, but if a weak pulse is detected, theprocessor 21 will cause the light 12 to emit a yellow or red color.Alternatively, two or more lights 12 may be employed, each chosen toemit a different color. As described above, the processor 21, relying onvalues stored in the processor's memory, will cause the intensity of thelight to increase or decrease, or the color of the light to change, inrelation to the strength or weakness of the detected pulse. Similarly,the processor 21 will cause the speaker 13 to increase or decrease thevolume, or change another characteristic of the emitted sound inrelation to the strength or weakness of the detected pulse. If theprocessor 21 detects a weak or declining pulse, the processor 21 willcause a color-changing LED light 12 to change in color, for example fromgreen to red, or will shift the visual indicator from one color (e.g.,green) light to a different color (e.g., yellow or red) light.Similarly, the processor 21 may cause the speaker 13 to emit a differentsound as a weak or declining pulse is detected. If a pulse is lost, theprocessor 21 can cause a color-changing LED light 12, or a separatelight, to emit a continuous bright, emergency red light. Similarly, ifno pulse is detected or if a pulse signal fades completely, theprocessor 21 may cause the speaker 13 to emit a shrill continuousemergency sound.

In operation, the continuous cardiac Doppler monitor patch 10 will beapplied to a patient 5 when a continuous pulse needs to be identified.The monitor patch 10 is activated or turned on by a switch 19, thepeel-off layer 17 is removed, exposing the adhesive 15, and the monitorpatch 10 is placed over a subject's 5 artery 6. It will be appreciatedthat the sequence of activating the switch 19 and removing the peel-offlayer 17 may be reversed. In an alternative embodiment, the removal ofthe peel-off layer 17 will turn on or activate the circuitry 16 of themonitor patch 10, either by turning a switch 19 to the active “on”position or by closing the on/off circuit 32 to the power source 28. Bydeactivating the circuitry 16 of the monitor patch 10, or cutting offpower from the power source 28, the switch 19 allows the monitor patch10 to be inactive for long periods of time, such as during storage, yetbe available in an instant when needed. When the monitor patch 10 isturned on, the processor 21 will direct the transducer 23 to send andreceive ultrasonic signals, 26 and 27, from the transmitters/receivers18. The transmitted and received signals, 26 and 27, may be combined, orthe reflected signals 27 alone may be analyzed by the processor 21 andcompared to values stored in the processor's 21 memory. If the combined,16 and 27, or reflected signals 27 correspond to a stored value forblood pumped by a heart, the processor 21 will cause the light 12 toblink in synchronization with the pulse and with an intensitycorresponding to the strength or weakness of the pulse. Similarly, theprocessor 21 will cause the speaker 13 to beep in synchronization withthe pulse and with a volume corresponding to the strength or weakness ofthe pulse.

The monitor patch 10 may be used on unstable patients or patients withthe potential of instability. Identifying the absence of a pulse isparamount to initiating CPR. The monitor patch 10 can also be appliedwhile patients 5 are in motion. For example, moving patients 5 downstairs or transporting patients 5 in a helicopter. Moving patients 5downstairs requires that the transporting personnel be at the head andfoot of the stretcher, where they are unable to verify a continuouspulse. Similarly, air medical evacuations, and even automotivetransportation, are loud and vibrations distracting, interfering withthe detection of a pulse. For example, it is difficult to feel a pulseor auscultate a heart beat in a helicopter. The monitor patch 10 uses alight 12 as proof of a heart beat and pulse. Moreover, in low visibilityenvironments, the monitor patch 10 uses a speaker 13 as proof of a heartbeat and pulse.

The monitor patch 10 will, preferably, be placed on a large artery 6,such as the carotid, radial, or femoral arteries. The monitor patch 10can be also located on the chest wall, since the ejection of blood fromthe aortic valve can be captured by the reflected Doppler signal 27.Ideally, the monitor patch 10 will be placed on the patient's 5 leftcarotid artery 6 (7A in FIG. 4). The left carotid will be the mostcommon site of placement because of infrequent procedural use, a largepulse wave, and its location away from the patient's 5 chest. The chestis needed for ECGs, defibrillator pads, and chest compressions. Themonitor patch 10 of the present invention is designed as a stand-alonethat integrates the switch 19, light 12, speaker 13, circuitry 16, base11, conductive pad 14, and adhesive layer 15 into a unitary and compactdevice configured to conform and adhere to the contours of a subject's 5skin above an artery 6. Ideally, a small patch of about 2½ inches indiameter, or about 5 square inches, will conform easily to the contoursof the patient's skin and reside over an area where arterial blood maybe detected. Stand-alone monitor patches of the invention may be largerto provide more space for circuitry and cover greater area over anartery; such stand-alone monitor patches are not limited in size, but alarger patch will be cumbersome and difficult to apply. It is preferred,but not required that stand-alone monitor patches cover areas of lessthan about twenty square inches.

The monitor patch 10 will be able to generate visual 12 and auditory 13signals. The signal will increase and decrease in intensity based on thepulse wave generated by the heart. This enables the medical provider todetermine if the patient's 5 pulse is strong, weak, or absent. Thesignals (light & sound) also vary in intensity with a diminishing orincreased pulse wave. This enables the medical provider to determine ifa pulse is weakening or stopping and the provider will be able to takeappropriate actions and determine if a treatment is working by anincreased pulse signal.

The monitor patch 10 of the present invention can monitor dynamicchanges in unstable or potentially unstable patients. With thisinformation the medical provider can use the intensity of thelight/sound signal to closely follow the pulse wave and mange therapy inreal time. This feature is especially helpful in evaluating theeffectiveness of CPR. A strong signal will signify adequate CPR,improving success to Return of Spontaneous Circulation (ROSC).

The monitor patch 10 can also detect blood flow to an extremity, therebyproviding information about the exact time of ischemia (inadequate bloodflow) or changes in blood flow. This can be used to monitor forcompartment syndrome, violation of the neurovascular bundle, or anembolic event to a large extremity.

The invention also provides a simple continuous cardiac Doppler monitorpatch 10 for checking fetal distress in pregnancy.

FIGS. 5 through 9 show an alternative embodiment of the stand-alonecontinuous cardiac Doppler pulse monitoring patch that provides visualand auditory signals that a pulse is detected or not detected in asubject. In this embodiment, the patch 40 is shaped in a “butterfly”configuration to straddle a subject's throat so that each wing, 41A and41B, covers that part of the throat over the left 7A and right 7Bcarotid arteries. In this position, the monitor 40 detects a pulse fromeither the left 7A or right 7B carotid arteries or both. As notedpreviously, the carotid artery is a useful position to detect pulse,since it leaves the subject's chest free for CPR or other procedures toaddress cardiac arrest. The butterfly monitor patch 40 may be placedover other arteries, such as the femoral or radial arteries. Each wing,41A at the left and 41B at the right, of the butterfly patch 40 includesan array of transmitters/receivers, 48A and 48B, respectively. Asdescribed above, the transmitters of each array, 48A and 48B, emitultrasonic waves, 66A at the left and 66B at the right, and thereceivers, 67A at the left and 67B at the right, detect reflected waves.The reflected wave signals, 67A and 67B, are demodulated and analyzed bya processor 61 to determine whether the reflected wave patterncorresponds with Doppler shift signals indicative of flowing blood, asdescribed above. Since blood from a heart is pumped in rhythmic pulses,the received Doppler shift signals will indicate that pattern and thememory in association with the processor 61 will provide data of modelsindicative of heart pulse patterns. Once a blood flow is detected, theprocessor 61 may cause a light 42 to emit light or blink insynchronization with the rhythm of the heart's pulses. Similarly, theprocessor 61 may cause a speaker 43 to emit a sound, such as a beep, insynchronization with the rhythm of the heart's pulses. As noted above,the processor 61 will also analyze the reflected wave signals, 67A and67B, for their strength by comparing them to known values stored in theprocessor's 61 memory. Using the stored values, the processor 61 willcause the light 42 to blink with an intensity corresponding to thestrength or weakness of the detected pulse. Similarly, based on thestored values, the processor 61 will cause the speaker 43 to beep with avolume corresponding to the strength or weakness of the detected pulse.

The butterfly patch 40 is placed over the front of the subject's 5 neck6 so that the left wing 41A is over the left carotid artery 7A and theright wing 41B is over the right carotid artery 7B. The butterfly patch40 can include an on/off switch 49, or it can be turned on in some othermanner, such as removal of the peel-away layer 47, as described above.Alternatively, the butterfly patch 40 could be connected through a port55 by a conductive cable 74, such as the arrangement shown in FIG. 10and described below, to a separate display unit 70, which can turn thebutterfly patch 40 on or off. Once on, the Doppler transmitters andreceivers, 48A and 48B, will begin transmitting ultrasonic signals, 66Aand 66B, and receiving their reflections, 67A and 67B. When blood isflowing, the Doppler effect on the reflected signals will be identifiedby the monitor's 40 circuitry 46, described below, as indicative of theblood's flow velocity, as well as of the frequency of pulses aspulsations of the blood from the heart's pumps is recognized. Thisrhythmic pulse will be indicated by a blinking light 42 and may furtherbe indicated by an audible sound from a speaker 43.

In a preferred embodiment, the butterfly monitor patch 40 is designedfor use with a cervical collar (“C-collar”, not shown) around thesubject's 5 neck 6, which is common practice in emergency conditions,and in which situations the detection of a pulse is of great importanceto medical personnel. To adapt the patch 40 for such use, it should beflat so that a C-collar will fit over the patch 40. Many C-collarsinclude a front opening that exposes the subject's 5 trachea. The light42, speaker 43, on/off switch 49, and connector port 55 may be locatedon the middle portion 41C of the butterfly patch 40, so as to beaccessible and visible through the C-collar's tracheal opening. If thepatch 40 is connected by a cable 74 to a separate unit 70, the cable 74can reach the patch 40 through the C-collar's tracheal opening.

FIG. 8 illustrates the parts of the butterfly monitor patch 40. A base41 supports circuitry 46. Under the base 41 is a conductive pad 44 toenhance transmission and reception of the ultrasonic waves from thecircuitry 46 to the patient. As described above, the conductive pad 44may be a thermoplastic gel or a hydrogel. Hydrogels are hydrophilicnetworks of polymer chains and may be free-standing or contained withina thin membrane. Beneath the conductive pad 44 is a thin adhesive layer45 to fix the patch 40 to the subject's 5 skin. A peel-off layer 47 isdisposed over the adhesive layer 45 to cover and preserve the adhesiveuntil used. Mounted on the base 41 is the circuitry 46, described below.The circuitry 46 may be mounted on a printed circuit board (PCB), whichmay be rigid, but, in a preferred embodiment, has some flexibility toconform to the subject's body. The monitor patch 40 may include a light42, speaker 43, and a switch 49. The switch 49 may turn the patch 40 onor off by activating the circuitry 46, disconnecting power from thepower source 68, or the switch 49 may have additional settings. Thus,the switch 49 may turn on the processor 61 and transmitters/receivers,48A and 48B, and cause the light 42 and speaker 43 to indicate thepresence or absence of a pulse, as well as the strength of the pulse, asdescribed above. Or, the switch 49 may have a setting to turn on thelight 42 but keep the speaker 43 off, so that the subject's 5 rest isnot disturbed. Or, the switch 49 may turn off both the light 42 and thespeaker 43 and transmit the pulse data over the cable 74 to a separatedisplay unit 70 (shown in FIG. 10), where the pulse can be indicated bythe display unit's 70 light 72A, speaker 73, or graphic display 71. Byremoving the pulse light and speaker signals from the subject 5 to aremotely located display unit 70, the subject 5 is allowed to restundisturbed. Similarly, a subject's 5 cardiac status can be monitored ata distance when the subject 5 is not physically near medical personnel,such as when a subject 5 is trapped in a dangerous location orundergoing treatment, such as X-rays or MRI, where medical personnelmust remain at a distance.

FIGS. 8 and 9 show more detail of the circuitry 46 of the butterflypatch monitor 40. A power source 68, such as a small battery, providesintegrated power to the electronic components. An on/off switch 49 onthe patch 40 can be used to activate the circuitry 46 of the patch 40.As with the previous embodiment, alternative mechanical or electronicswitching arrangements may be employed, such as a mechanical switch thatactivates the circuitry 46 when the peel-away layer 47 is removed. Atransducer 63 includes transmitters/receivers, 48A and 48B, arrayed inor over the base 41. The transmitters emit ultrasonic waves, 66A and66B, and the receivers detect reflected waves, 67A and 67B. Thereflected wave signals, 67A and 67B, are demodulated and analyzed by aprocessor 61, or the transmitted ultrasonic wave signals may be combinedwith the demodulated reflected wave signals, 67A and 67B, for analysisby the processor 61, to determine whether the reflected wave patternscorrespond with Doppler shift signals indicative of flowing blood. Sinceblood from a heart is pumped in rhythmic pulses, the received Dopplershift signals will indicate that pattern, as described above. Once bloodflow is detected, the processor 61 causes a light 42 to blink insynchronization with the rhythm of the heart's pulses. Similarly, theprocessor 61 will cause a speaker 43 to emit a sound, such as a beep, insynchronization with the rhythm of the heart's pulses. The processor 61will also analyze the reflected wave signals, 67A and 67B, for theirstrength by comparing them to known values stored in the processor's 61memory. Using the stored values, the processor 61 will cause the light42 to blink with an intensity corresponding to the strength or weaknessof the detected pulse. As with the previous embodiment, the light 42 maybe a single LED light source capable providing different colors orvarying intensities of brightness, or more than one light may be used toaccomplish this, and, if no pulse is detected or if a detected pulsefades away, an emergency alarm light, such as a bright red light, may beactivated. Similarly, based on the stored values, the processor 61 willcause the speaker 43 to beep in with a volume corresponding to thestrength or weakness of the detected pulse and, if no pulse is detectedor if a pulse signal fades completely, the processor 61 may cause thespeaker 43 to emit a shrill continuous sound.

Referring FIGS. 10 through 12, in an alternative embodiment, astand-alone continuous cardiac Doppler pulse monitoring patch 51 isconnected by one or more conductive data cables 74 to a remote displayunit 70. In this embodiment, a patient's blood flow and pulse can beremotely monitored by medical personnel. This capability allows medicalpersonnel to monitor a subject's blood flow remotely when the subject isundergoing procedures, such as X-ray or an MRI, where the light 52 onthe patch 51 cannot be seen or the speaker 53 cannot be heard, or whenthe subject is located in a dangerous area, such as a collapsedbuilding. Also, when a subject is resting, it is possible to turn offthe speaker 53 and light 52 on the patch 50 to prevent disturbing thepatient, yet continue to monitor the subject's blood flow remotely fromthe display unit 70. By providing a data cable 74, it is also possibleto download data from the memory of the processor 81 of the patch 51. Inthis way, the patch 51 can store detected cardiac pulse data, which canbe downloaded via the data cable 74 to the display unit 70 or a separatecomputing device and later and analyzed. For example, when emergencymedical technicians reach a subject, the stand-alone monitor patch 51(or the butterfly monitor patch 40 or the wireless monitor patch 90) isactivated, applied to the subject, detects a pulse, and the memory inassociation with the processor 81 begins saving data of the subject'spulse. Later, for example, when the subject reaches hospital, thestand-alone monitor patch 51 (or the butterfly monitor patch 40 or thewireless monitor patch 90) is connected by a data cable 74 to thedisplay unit 70 or a separate computing device and the subject'shistorical pulse data may be and analyzed to evaluate the heart'sbehavior from the time the monitor patch was applied.

To accommodate this system 50, the patch 51 includes a port 55 that mayreceive one or more connectors 76 of one or more conductive cables 74.As noted above, the patch 51 is formed by a base 54, which supports thecircuitry 56. The circuitry 56 includes transmitter and receiver units58 on or incorporated into the base 54. Under the base 54 is aconductive pad 57, as described above. Beneath the conductive pad 57 isa thin adhesive layer 59 to fix the monitor patch 51 to the subject'sskin. A peel-off layer 60 is disposed over the adhesive layer 59.Mounted on the base 54 is the circuitry 56, described below. Thecircuitry 56 may be mounted on a printed circuit board (PCB), which maybe rigid, but, in a preferred embodiment, has some flexibility toconform to the subject's body. Over the circuitry 56 are one or morelights 52 and a speaker 53 and, in some embodiments, a manual on/offswitch may be included, such as has been described above. The port 55shown in FIGS. 10 and 11 is directed to receive a connector 76 from theside, along the plane of the base 54, which is a preferred orientationwhen the patch 51 is placed over one of the subject's carotid artery, sothat the cable 74 will not project away from the neck, which couldinterfere with a C-collar or present an obstruction to the subject andmedical personnel. In contrast, the butterfly monitor patch 40 shown inFIGS. 5 through 9 has a connector port 55 in the middle portion 41Cdirected to receive the connector 76 from above, normal to the plane ofthe base 41, which places the light 42, speaker 43, switch 49, connectorport 55, and cable 74 within the tracheal opening provided in manycervical collars. The embodiments shown have a single port 55, connector76 and cable 74, but multiple ports and cable connectors could beaccommodated.

The cable 74 connects to the remote display unit 70 through a port 75.The cable 74 may be permanently connected to the display unit 70 or thecable may have a connector 76 so that it may be disconnected. In theembodiment shown in FIG. 10, the display unit 70 has two lights, 72A and72B, so that the heart rhythm and flow strength can be indicated on onelight or light cluster 72A and an emergency light indicator 72B can showthat the subject's heart has stopped pumping blood or is dangerouslyclose to doing so. The display unit 70 also has a speaker 73 to providean audible indicator the subject's heart rhythm and strength, and thespeaker may also provide an emergency sound to indicate that thesubject's heart is or has failed. The unit 70 may also include a graphicdisplay screen 71 to provide textual, numerical and graphicalinformation about the subject's blood flow, such as a numerical displayof heart rate (bpm) and blood velocity (cm/s), as well as a waveform toshow the strength of the subject's pulse, pressure, and blood velocityover time. A switch 149 is provided to turn the display unit 70 on oroff.

Referring to FIGS. 11 and 12, in one embodiment, the stand-alone monitorpatch 51 has its own power source 80, such as a small battery, toprovide integrated power to the electronic components. A switch, as inpreviously disclosed embodiments may also be incorporated into the patch51. A transducer 84 includes transmitters/receivers 85 (shown as units58 in FIG. 12) arrayed in or over the base 54. The transmitters emitultrasonic waves 86 and the receivers detect reflected waves 87. Asdescribed above, the reflected wave signals 87 are demodulated andanalyzed by a processor 81 to determine whether the reflected wavepattern corresponds with Doppler shift signals indicative of flowingblood. Once a blood flow is detected, the processor 81 causes the light52 to blink in synchronization with the rhythm of the heart's pulses.Similarly, the processor 81 will cause a speaker 53 to emit a sound, abeep, in synchronization with the rhythm of the heart's pulses. Theprocessor 81 will also analyze the reflected wave signals 87 for theirstrength by comparing them to known values stored in the processor's 81memory. Using the stored values, the processor 81 will cause the lightor lights 52 to blink with an intensity corresponding to the strength orweakness of the detected pulse. Similarly, based on the stored values,the processor 81 will cause the speaker 53 to beep in with a volumecorresponding to the strength or weakness of the detected pulse.

The patch 51 is connected to the display unit 70 by cable 74, aspreviously disclosed. The display unit 70 has its own power source 78 topower its components. The display unit's 70 processor 79 receives theheart flow and velocity data from the patch 51 and causes one or morelights 72A to display the pulse in the manner described above, Ano-pulse light 72B can provide a visual signal that the subject's pulsehas failed. A speaker 73 can emit sounds to provide audible signals ofthe subject's pulse. A display 71 provides textual, numerical andgraphical information about the subject's blood flow, such as anumerical display of pulse rate (bpm) and blood velocity (cm/s), as wellas a waveform to show the strength of the subject's pulse, pressure, andblood velocity over time. The processor's 79 memory can store data ofthe subject's cardiac status over time by downloading such data from thestand-alone monitor patch 51 processor's 81 memory and from the displayunit's 70 processor's 79 memory, and this historical data may bedisplayed on the unit's 70 screen 71 or transmitted to other medicalequipment for analysis.

Referring to FIG. 13, an alternative embodiment is disclosed whereby aremote display unit 70 includes a power source 78 to provide power to amonitor patch 90 over a power and data cable 98 to power the patchcomponents, such as the processor 91, transducer 94,transmitters/receivers 95, light(s) 92, and speaker 93. The display unit70 is a compact, hand-held box, capable of accommodating more batterypower, processing, and memory, and display options than the patch 90 canprovide. In a basic embodiment, the unit 70 is very compact and includesonly one indicator of the subject's blood flow, such as the light 72.

Referring to FIGS. 14 and 15, an alternative embodiment is disclosedwhereby the stand-alone monitor patch 100 transmits 111 and receives 100wireless data signals from the remote display unit 70. In thisembodiment, the patch 100 includes its own power source 101 andtransmitter/receiver 109. The display unit 70 also has atransmitter/receiver 77 to receive and send data to the patch 50.

Referring to FIG. 16, another alternative embodiment is disclosedwhereby the display unit 70 provides power from a power source 78 andprocessing from a processor 79 via a power and data cable 121 to asimplified monitor patch 120 to power the transducer 123 andtransmitters/receivers 122, which operate as described above. Thesimplified monitor patch 120 is less expensive to make, since it hasfewer components, and may discarded after use, while the display unit 70may be re-used.

The drawings and description set forth here represent only someembodiments of the invention. After considering these, skilled personswill understand that there are many ways to make acontinuous Dopplercardiac pulse monitor patch according to the principles disclosed. Theinventor contemplates that the use of alternative structures, materials,or manufacturing techniques, which result in a monitor patch accordingto the principles disclosed, will be within the scope of the invention.

1. A stand-alone continuous Doppler heart monitor patch comprising: abase having an upper base surface and a lower base surface on a sideopposite the upper base surface, circuitry disposed on the upper basesurface, the circuitry comprising at least one transducer configured totransmit ultrasound waves in a direction beyond the lower base surfaceand receive reflected ultrasound waves, a digital to analog converterfor converting transmitted digital ultrasound wave signals from aprocessor to converted ultrasound waves and delivering the convertedultrasound waves to the transducer, an analog to digital converter forconverting reflected ultrasound waves from the transducer to reflecteddigital ultrasound wave signals and delivering the reflected digitalultrasound wave signals to the processor, a power source providing powerto the circuitry, and memory in association with the processor, whereinthe processor delivers the transmitted digital ultrasound wave signalsto the digital to analog converter and controls transmission ofultrasound waves by the transducer, and wherein the processor processesthe reflected digital ultrasound wave signals, a pad formed of soundconducting gel, the pad having an upper pad surface and a lower padsurface opposite to the upper pad surface, wherein the upper pad surfaceis disposed on the lower base surface, an adhesive layer having an upperadhesive surface and a lower adhesive surface opposite the upperadhesive surface, wherein the upper adhesive surface is disposed on thelower pad surface, and wherein the lower adhesive surface is adapted toadhere releaseably to skin of a human, a peel-away sheet disposed on thelower adhesive surface, wherein the peel-away sheet is removable fromthe lower adhesive surface to expose the lower adhesive surface, andwherein the patch is adapted and to conform to a contour of the skinover an artery and the patch is sized to fit on the skin over a portionof the artery, wherein the processor is adapted to detect a detectedblood pulse in the artery from the transmitted digital ultrasound wavesignals and the reflected digital ultrasound wave signals, wherein theprocessor causes a blood pulse signal to be emitted indicative of thedetected blood pulse in the artery, and wherein the base, circuitry,pad, adhesive layer, and peel-away sheet are integrated into the patchand the patch is capable monitoring the detected blood pulse andemitting the blood pulse signal independent of any external device. 2.The stand-alone continuous Doppler heart monitor patch of claim 1wherein the blood pulse signal comprises a light source to emit light inresponse to the detected blood pulse.
 3. The stand-alone continuousDoppler heart monitor patch of claim 2 wherein the light emitted inresponse to the detected blood pulse comprises a variable lightintensity proportional to a strength of the detected blood pulse, andwherein the light emitted in response to the detected blood pulsefurther comprises an emergency light activated when the processordetects an absence of the detected blood pulse in the artery.
 4. Thestand-alone continuous Doppler heart monitor patch of claim 3 whereinthe blood pulse signal comprises a speaker to emit sound in response tothe detected blood pulse.
 5. The stand-alone continuous Doppler heartmonitor patch of claim 4 wherein the sound emitted in response to thedetected blood pulse comprises a variable sound intensity proportionalto the strength of the detected blood pulse, and wherein the soundemitted in response to the detected blood pulse further comprises anemergency sound activated when the processor detects an absence of thedetected blood pulse in the artery.
 6. The stand-alone continuousDoppler heart monitor patch of claim 4 further comprising a switch toactivate the circuitry from an inactive state.
 7. The stand-alonecontinuous Doppler heart monitor patch of claim 6 wherein the switch isactivated when the peel-away sheet is removed from the lower adhesivesurface.
 8. The stand-alone continuous Doppler heart monitor patch ofclaim 1 wherein the circuitry is incorporated onto a printed circuitboard and wherein the base and the printed circuit board are flexible.9. The stand-alone continuous Doppler heart monitor patch of claim 1further comprising a connector port for communicating data from thepatch to an external device.
 10. The stand-alone continuous Dopplerheart monitor patch of claim 9 further comprising a conductive cablereceived by the connector port and wherein the conductive cablecommunicates the data from the patch to the external device.
 11. Thestand-alone continuous Doppler heart monitor patch of claim 9 whereinthe connector port comprises a wireless transceiver for communicatingthe data from the patch to the external device.
 12. The stand-alonecontinuous Doppler heart monitor patch of claim 9 wherein the externaldevice comprises a display unit comprising at least one display unitlight source, a display unit speaker, and a graphic display, wherein thedisplay unit light source emits light in response to the detected bloodpulse, the display unit speaker emits sound in response to the detectedblood pulse, and the graphic display provides a graphical display ofblood pulse over time of the detected pulse.
 13. The stand-alonecontinuous Doppler heart monitor patch of claim 9 wherein the memory inassociation with the processor stores blood pulse data of the detectedblood pulse over time, and wherein the blood pulse data may be accessedby the external device via the connector port.
 14. The stand-alonecontinuous Doppler heart monitor patch of claim 1 further comprising asecond base having a second upper base surface and a second lower basesurface opposite the second upper base surface, at least one second basetransducer configured to transmit second base ultrasound waves in asecond base direction beyond the second lower base surface and receivesecond base reflected ultrasound waves, wherein the second basetransducer is disposed on the second upper base surface, and wherein theprocessor is further adapted to detect the detected blood pulse in theartery from the second base transmitted ultrasound waves and the secondbase reflected ultrasound waves, a second base pad formed of soundconducting gel, the second base pad having a second base upper padsurface and a second base lower pad surface opposite the second baseupper pad surface, wherein the second base upper pad surface is disposedon the second base lower base surface, a second base adhesive layerhaving a second base upper adhesive surface and a second base loweradhesive surface opposite the second base upper surface, where thesecond base upper adhesive surface is disposed on the second base lowerpad surface, and wherein the second base adhesive layer is adapted toadhere to skin of a human, a second base peel-away sheet disposed on thesecond base lower adhesive surface, wherein the second base peel-awaysheet is removable from the second base lower adhesive surface to exposethe second base adhesive layer, and wherein the patch is further adaptedand sized to fit and conform to the contour of the skin of a neck sothat the base is located over one of the left or right carotid arteriesand the second base is located over an other of the of the left or rightcarotid arteries.
 15. The stand-alone continuous Doppler heart monitorpatch of claim 14 wherein the blood pulse signal of the patch is locatedbetween the base and the second base over the neck between the left andright carotid arteries and the pulse signal is further located to beobservable through an opening in a cervical collar.
 16. A continuousDoppler heart monitor patch and display unit system comprising: a patchconfigured to adhere to skin over an artery of a patient, the patchcomprising a conductive gel layer forming a surface of the patch, anadhesive layer disposed on the surface and adapted to adhere the patchto the skin of the patient, a plurality of transducers for transmittingultrasound waves through the conductive gel and adhesive layers and forreceiving reflected ultrasound waves, and a conductive cable inelectrical communication with the plurality of transducers, and aportable display unit comprising a port for receiving the conductivecable, a digital to analog converter, an analog to digital converter, aprocessor, memory, a blood pulse display, and a power source, whereinthe processor transmits ultrasound wave digital signals to the digitalto analog converter, the digital to analog converter converts theultrasound wave digital signals from the processor to convertedultrasound waves and transmits the converted ultrasound waves over theconductive cable to the plurality of transducers in the patch, theanalog to digital converter receives the reflected ultrasound waves fromthe plurality of transducers in the patch over the conductive cable, theanalog to digital converter converts the reflected ultrasound waves toreflected ultrasound wave digital signals and transmits the reflectedultrasound wave digital signals to the processor, the processorprocesses the ultrasound wave digital signals and reflected ultrasoundwave signals to detect blood flow in the artery of the patient, and theprocessor causes the blood pulse display to emit an observable signalcorresponding to the blood flow.
 17. The continuous Doppler heartmonitor patch and display unit system of claim 16 wherein the bloodpulse display comprises a light source, a speaker, and a screen, whereinthe light source is configured to emit light corresponding to the bloodflow, the speaker is configured to emit sound corresponding to the bloodflow, and the screen is configured to provide a graphic visual displayof a pulse frequency of the blood flow, and wherein one or more of thelight source, speaker, and screen may be activated or deactivated.
 18. Amethod of monitoring blood flow in a patient comprising the steps of:providing a stand-alone continuous cardiac Doppler patch configured toconform to contours of skin over an artery of a patient and wherein thepatch is limited to a size under twenty square inches and to fit over aportion of the artery, the patch comprising a base, an adhesive layerhaving an upper adhesive surface and a lower adhesive surface oppositethe upper adhesive surface, the lower adhesive surface adapted to adherereleaseably to the patient's skin, wherein the upper adhesive surface isdisposed on a lower surface of the base, a peel-away sheet covering thelower adhesive surface, electronic components provided on an uppersurface of the base, the electronic components comprising a powersource, a processor, memory in association with the processor, a digitalto analog converter, an analog to digital converter, transducers, apulse detection signal, and a switch to activate the electroniccomponents, removing the peel-away layer and exposing the lower adhesivesurface and adhering the patch to the patient's skin over the artery,operating the switch to activate the electronic components, wherein theprocessor generates an ultrasound wave digital signal and transmits theultrasound wave digital signal to the digital to analog converter, thedigital to analog converter converts the ultrasound wave digital signalto a converted ultrasound wave, the digital to analog convertertransmits the converted ultrasound wave to at least one of thetransducers, in response to receiving the converted ultrasound wave theat least one of the transducers emits a transmitted ultrasound wavetoward the patient's artery, the transducers receive reflectedultrasound waves, the transducers transmit the reflected ultrasoundwaves to the analog to digital converter, the analog to digitalconverter converts the reflected ultrasound waves to reflectedultrasound wave digital signals and transmits the reflected ultrasoundwave digital signals to the processor, the processor receives thereflected ultrasound wave digital signals and analyzes the ultrasoundwave digital signal and the reflected ultrasound wave digital signal todetermine whether a blood pulse is detected in the patient's artery, theprocessor causes the pulse detection signal to emit a pulse signalcorresponding to a strength and a frequency of the blood pulse whenblood pulse is detected and the processor causes the pulse detectionsignal to emit a no-pulse signal when blood pulse is not detected,observing the pulse detection signal, initiating cardiac resuscitationtreatment when the no-pulse signal is observed, and determining whethercardiac resuscitation treatment is needed when the pulse detectionsignal emits a pulse signal corresponding to a weak blood pulse.